<< Maybe I am missing something here, but I was under the impression that you needed a custodian to hold the assets for you in the form of a solo 401k account, no? Last time I asked Schwab, for example, I was told that they do not offer such services. It isn't the administration you'd be getting from Fidelity, it is the asset-holding services, at least as far as I understand it. >>

OK, I see what you're asking here. Like with IRA's and other plans, an organization does have to have a plan to handle the accounting and paperwork for such a plan. But this doesn't necessarily mean there's any real “administration” of the plan going on like you might see in other qualified plans. And not every investment provider provides these or the same things. So, to get what one might really want, using a some pension administrator might be a good place to go as some administrators don't charge much for these.